我使用Django和Python 3.7。我用PyCharm创建一个项目，它创建以下目录结构（一些自定义添加的是我自己的）：
mainpage
__init__.py
__pycache__
admin.py
apps.py
fixtures
management
migrations
models.py
services.py
templates
mainpage
trending.html
tests.py
urls.py
views.py
mainpage_project
__init__.py
__pycache__
settings
wsgi.py
manage.py
templates
venv
文件“urls.py”看起来像下面
from django.contrib import admin
from django.urls import path
from . import views
urlpatterns = [
path('trending', trending, name='trending'),
]
我感到困惑，其中“urls.py”应该去它应该包含的内容。当我开始了我的服务器，它给了我下面的错误（“ModuleNotFoundError：无模块名为‘mainpage_project.urls’”）...
(venv) localhost:mainpage_project davea$ python manage.py runserver
Performing system checks...
Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x103096950>
Traceback (most recent call last):
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/utils/autoreload.py", line 225, in wrapper
fn(*args, **kwargs)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/core/management/commands/runserver.py", line 117, in inner_run
self.check(display_num_errors=True)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/core/management/base.py", line 379, in check
include_deployment_checks=include_deployment_checks,
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/core/management/base.py", line 366, in _run_checks
return checks.run_checks(**kwargs)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/core/checks/registry.py", line 71, in run_checks
new_errors = check(app_configs=app_configs)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique
all_namespaces = _load_all_namespaces(resolver)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces
url_patterns = getattr(resolver, 'url_patterns', [])
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/utils/functional.py", line 37, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/urls/resolvers.py", line 533, in url_patterns
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/utils/functional.py", line 37, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Users/davea/Documents/workspace/mainpage_project/venv/lib/python3.7/site-packages/django/urls/resolvers.py", line 526, in urlconf_module
return import_module(self.urlconf_name)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
File "<frozen importlib._bootstrap>", line 983, in _find_and_load
File "<frozen importlib._bootstrap>", line 965, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'mainpage_project.urls'
我的“urls.py”文件应该去哪里，应该怎么它包含哪些内容？
你在你的项目中urls.py失踪mainpage_project。即，
mainpage_project
__init__.py
__pycache__
settings
wsgi.py
urls.py #here
urls.py负责项目映射路线和路径。例如，如果你想显示什么东西在URL /趋势/，你必须在这里第一次映射。
从你的目录结构mainpage_project是你的项目，mainpage是您的应用程序。
每个应用程序可以有它自己的urls.py。 Django的其实你的项目文件夹内检查它。
典型urls.py的样子：
from django.conf.urls import url
from django.contrib import admin
from django.urls import path
from mainpage import views
urlpatterns = [
path('trending', trending, name='trending'),
]
UPDATE1：从评论，您要添加urls.py时候，因为你的urls.py里面你要导入从views的文件夹mainpage_project越来越导入错误。
from . import views
.符号是指从那里它被称为即，mainpage_project目录当前目录。
而且有mainpage_project目录里面没有views.py。但是views.py存在mainpage目录中。因此，更新为：
from mainpage import views